The present application relates to valves for controlling flow of a fluid. More especially, the application relates to a fail safe mechanism for power operated valves. The concepts disclosed herein have particular, but not exclusive, application to valves for controlling flow of one or more fluids. The concepts disclosed herein may have application to plumbing fittings and fixtures and water supply systems and installations for washing, showering, bathing and the like that employ such plumbing fittings and fixtures.
Power operated valves are known in which a valve member is moveable relative to a valve seat between open and closed positions by means of a linear actuator for controlling fluid flow. Such valves can be left in an open position in the event of a power supply failure allowing fluid flow to continue in an uncontrolled manner until the power supply is restored. The present application is intended to address this problem.